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  • Writer's pictureSim Elliott

Coed Felenrhyd and Llennyrch, Maentwrog, Wales. Wild flowers, ferns, bryophytes & lichens. 15.08.23

Updated: Aug 24, 2023

Coed Felenrhyd & Llennyrch is a rare, Atlantic oak woodland and one of our largest woods in Wales. It sits above the Vale of Ffestiniog and is fringed by the dramatic waterfalls of the Afon Prysor gorge in the Snowdonia National Park. Coed Felenrhyd & Llennyrch - Visiting Woods - Woodland Trust

I reached the Coed Felenrhyd's, just south of Maentwrog, by bus 3B from Porthmadog. I stayed in Porthmadog for five night,s in order to visit Coed Felenrhyd & Llennyrch; Coed Lletywalter; Coed Aber Artro; Coed Cymerau; and Coed Garth Gell by public transport. Celtic Rainforests Wales | Homepage gave me very useful information on how to get to these Celtic Rainforest by public transport form Porthmadog.

I reached Porthmadog by train from Brighton (via London Victoria, London Euston and Birmingham New Street).

I took the 3B bus from Porthmadog to Tan-y-bwlch, Oakeley Arms (one bus an hour, 45 minutes journey time); see: 3B - Porthmadog - Blaenau Ffestiniog – Llew Jones Coaches, Lloyds Coaches – From the bus stop ay the Oakeley Arms, I walked along the A487 (north eat) and then turned left (west) onto the A496 through Maentwrog and south to to the entrance of the reserve is next to (south of) the Maentwrog Hydro-eclectic Power Station (shown by the blue dots on this map). There is no pavement on the A496; so care needs to be taken. The walk from the bus stop to the entrance is about 30 minutes. This map and the details of public transport were very helpfully provided for me by Celtic Rain Forests Wales Coed Felenrhyd/Llennyrch | Celtic Rainforests Wales

I walked through the amazing Afon Prysor gorge to the Afon Prysor dam; one of four dams)which formed the Trawsfynydd reservoir to provide the water for the Maentwrog hydro-eclectic power station. I followed the routes suggested by the Woodland Trust; taking the Llenryhch Path, Gorge Circle and the Felenrhyd Loop trails (taking the northern sections of these three path to walk up to the Prysor Dam, and the southern sections of these paths to walk back to the Maentwrog Power Station). It took me 8 hours to walk to the dam and back to the PowerStation, but I stopped many times to take look at flora and lichens. Many of the paths are steep, wet and have many trip hazards (tree roots, rocks, slippery rocks etc.) and some ford streams. Walking boots with a good grip are essential and care needs to be taken at all times.

All sections of text in italics are quotations, sources sited.

The photographs in this post are ordered chronologically (the order in which I saw the things)

I am only an amateur naturalist; thus all identifications are provisional; if you note a mistake in identification please feel free to tell me. If you want to contact me about any aspect of this blog, email me at simeon[underscore]elliott[at]gmail[dot]com.

Atlantic Woodland / Temperate Rain Forest

The walk through the gorge is a wonderful opportunity to see flowering plants, ferns, bryophytes (mosses and liverworts) and lichens that are typical of Atlantic woodlands (temperate rain forests); some very rare outside this habitat. This post is not a record of a systematic survey of the species of Coed Felenrhyd and Llennyrch; it is a record of what I noticed and caught my attention as I was walking

The steep banks of the Afon Prysor are thought to have been wooded for thousands of years – possibly since trees first re-colonised Wales after the last Ice Age – and a walk here certainly feels like a journey back in time. It’s a magical place that echoes with birdsong and where gnarled oaks are festooned with mosses and ferns.

... The steep sides of the ravine are cloaked in sessile oak woodland with rowan and birch, with species such as ash, hazel and elm on milder soils. This woodland is designated as a SSSI for its Atlantic bryophytes, which thrive in the humid conditions of this temperate rainforest, where it can rain 200 days a year. The quality of the lower plant flora is of European and indeed global importance, a fact recognised by its inclusion within the Meirionnydd Oakwoods and Bat Sites Special Area of Conservation. Coed Felenrhyd/Llennyrch | Celtic Rainforests Wales

Theses woods are closely connected with Welsh mythology,

Coed Felenrhyd is mentioned by name (Melenrhyd, Y Felen Rhyd) in the famous collection of Welsh legends, the Mabinogion, as the last resting place of Pryderi, King of Dyfed, who was killed in single combat with Gwydion the trickster. These tales were written in the 12th century, but the oral tradition is much older. [It was said that Gwydion could summon an army of trees to battle. Inspiration for Tolkien perhaps? Woodland Trust information board].

Walks through Coed Felenrhyd trace some of the adventures of the famous Welsh mercenary and magician – Huw Llwyd. At the height of his fame, people who were plagued with demons would be publicly exorcised by Huw at his famous pulpit – a massive rock in the middle of the River Cynfal – which is still there today .Coed Felenrhyd & Llennyrch - Visiting Woods - Woodland Trust

The road walk between Tan-y-bwlch, Oakeley Arms and Maentwrog power station (the entrance to the reserve)

There was much introduced (and invasive) Himalayan balsam (Impatiens glandulifera) and Montbretia (Crocosmia aurea x pottsii = C. x crocosmiiflora) along the A487 (and I saw much of both species from the window as I was travelling on Cambrian Coast railway through north Wales). However, when walking done the A496 road past the village of Maentwrog to the Maentwrog Hydro-eclectic Power Station, the flora was that of Atlantic woodland: the sessile oaks, Quercus petraea, were covered in epiphytic polypody ferns, and there were many lichens and bryophytes. Atlantic woodland is not confined to nature reserves; it was/is the indigenous woodland of North Wales, and was widespread in North Wales until native woodland was cleared for farming, urban development or commercial forestry

Polypodium probably P. vulgare on Sessile Oak, Quercus petraea, aside the A496

Polypodium probably P. vulgare and Maidenhair Spleenwort, Splenium trichmanes grew all over the wall bordering the road

along with lichens Cladonia sp. probably C. pyxidata, Pixie Cup Lichen, and mosses Little Shaggy-Moss, Rhytidiadelphus loreus on the walls

Probably Hylocomiadelphus triquetrus, Big Shaggy-moss, on top of the road wall

Coed Felenrhyd and Llennyrch National Nature Reserve Maentwrog

The path through the reserve starts beside the Meantwrog Hydro-electric power station; i a 30MW hydroelectric station on the banks of the Dwyryd Estuary near Blaenau Ffestiniog in North Wales. It has been operating since 1928 and generates electricity using water, which falls as rain in the surrounding area and is collected in a series of rivers, 'leats' and streams that feed into Trawsfynydd lake. The water is carried by a pipeline to drive two turbines, which generate enough electricity to power around 12,000 local homes each year. Electricity Generation | Magnox Sites

Sphagnum palustre, Blunt-leaved Bog-moss, with capsules at the beginning of the path

Common Haircap Moss, Polytrichum commune, with capsules

Cow Wheat, Melampyrum pratense

Common cow-wheat is an annual of woodland edges, heaths and upland moors that has deep golden flowers from May to September. It is a hemi-parasitic plant, meaning that it relies on obtaining some of its nutrients from the roots of nearby plants. The nectar of Common Cow-wheat can only be reached by insects that have a long proboscis, especially bees. If the flower is not pollinated, it will pollinate itself. It is the larval foodplant of the rare Heath Fritillary butterfly. Common cow-wheat | The Wildlife Trusts

An old stone bridge near the power station

Water Earwort, Scapania undulata; a characteristic liverwort of wet conditions. S. undulata is the commonest British Scapania, and often abundant in wet places. Its most typical habitats are rocks in streams and rivers, and flushes and springheads in the uplands. Scapania-undulata.pdf (

Hard Fern, Blechnum spicant, next to waterfall. (Hard Ferns are common too in Sussex's oceanic ghyll woodlands)

the fronds are single pinnate, which means that the individual leaflets the frond is divided into, known as the pinnae, aren’t further divided. They grow directly opposite each other on the stem which gives them a herringbone appearance. They taper in at both the tip and the bottom of the stem. Hard fern is dimorphic, which means it has two types of frond – sterile and fertile. The sterile foliage has long, flat, leathery, dark green fronds with slightly wavy edges. They arch outwards, almost parallel to the ground, and can grow up to 30cm. The fertile fronds are longer, narrower and upright. They grow in the centre of the plant with their leaflets spaced further apart from each other, and the outer edges rolled inwards on the undersides. Hard Fern (Blechnum spicant) - British Plants - Woodland Trust

Waterfall in one of the tributary stream flowing in to the Afon Prysor; there are many such tributary stream with waterfalls.

Tunbridge Wells Filmy Fern, Hymenophyllum tunbrigense, on rocks next to the path

A rhizomatous, perennial, mat-forming fern of very sheltered, often deeply shaded, humid habitats; these include acidic rock faces, humic banks and tree trunks, particularly in deep wooded stream valleys, and crevices on upland boulder scree. 0–⁠760 m. The distribution of H. tunbrigense is now largely stable, due in part to fuller and more intensive searching, with the majority of losses having occurred before 1930, though a further fifth of sites in south-eastern England were lost by the end of the 20th century, largely through woodland loss and shading by Rhododendron ponticum. It is likely to survive in many of the sites in western Scotland where it has not been recorded this century.

It can be found in Sussex, im the High Weald ghyll woods, including Eridge Rocks, and The Rocks, Tunbridge Wells, after which it is named, but I have never seen it in Sussex.

Common Pellia, Pellia epiphylla with Silky Forklet-Moss, Dicranella heteromalla on the same rocky outcrop.

Bank Haircap Moss Polytrichum formosum on the forest floor

Probably Northern Peatmoss, Sphagnum capillifolium agg.

Enchanter's-Nightshade, Circaea lutetiana; very common in all woodlands in the UK. The genus Circaea is named after Circe, the enchantress daughter of the god Helios in Greek mythology. The specific epithet lutetiana comes from Lutetia, the Latin name for the city of Paris, which is sometimes referred to as the city of witches. Circaea lutetiana - Enchanter's Nightshade (

An Usnea lichen, possibly U. florida, on Sessile Oak

Heath Bedstraw, Galium saxatile, growing with a Spagnum sp. moss on the forest floor

Common Heather, probably with a Bog Hover Fly Sericomyia silentis; along the path. Sericomyia silentis is widespread and abundant in northern and western Britain, especially west Wales, the Pennines and other upland areas of northern England, and in upland Scotland. In the lowlands of southern and eastern England it is much scarcer, probably breeding on heathland and other more acid habitats, although adults may be found some distance from such localities. Species details | Hoverfly Recording Scheme

Common Smoothcap, Atrichum undulatum, with other mosses

Polypodium sp. fern and Common Tamarisk-Moss, Thuidium tamariscinum, on Sessile Oak, Quercus petraea

Ferns, probably, Male fern Dryopteris filix-mas

Saccogyna viticulosa, Straggling Pouchwort; an Atlantic woodlands species

Frullania tamarisci, Tamarisk Scalewort on Sessile Oak; a liverwort of Atlantic woodland; but is also found in oceanic ghyll woods of Sussex

Another Usnea sp. lichen

Little Shaggy-Moss Rhytidiadelphus loreus, Broom Forkmoss, Dicranum scoparium and a liverwort

Little Shaggy-Moss Rhytidiadelphus loreus and Hammered Shield Lichen Parmelia Sulcata

Prysor Gorge

Tributary stream running into the Afon Prysor

A group of fungi; possibly an Inkcap Coprinellus sp. and possible Sulphur Tufts, Hypholoma fasciculare, and others

An Usnea, Beard, lichen, possibly Usnea Florida, Flowery lichen, on Sessile Oak.

One of the crossings of a tributary stream

Another beautiful tributary of the Afon Prysor

Hooded Tube Lichen. Hypogymnia physodes; widespread across the UK, but preferred habitat is on acid-barked trees and heather (Calluna) stems, also terrestrial on base-poor dunes. Hypogymnia physodes | NatureSpot

Upland Heath and Bog around Llyn Trawsfynyd

(the reservoir formed by the damming of the Afon Prysor)

Heathers, Bell Heather, Erica cinerea, and Common (ling) Heather, Calluna vulgaris, and Bracken, Teridium aquilinum

Common Heather, Calluna vulgaris

Cross-leaved Heath, Erca tetralix and Bell Heather, Erica cinerea

Bog Myrtle, Myrica gale. Relatively common in northern and western bogs, but very rare where I live in Sussex. so a pleasure to see (only recorded in Sussex at Leonardslee, West Sussex)

Bog Asphodel Narthecium ossifragum . Relatively common in western and northern bogs, but very rare where I live in Sussex. so a pleasure to see (only recorded in Sussex at Hesworth, West Sussex)

Rhizocarpon geographicum, Map Lichen, on granite; common on upland granite

The path through the bog, with Bog Myrtle each side

View of the mountains around the reservoir

Variegated Foam Lichen, Stereocaulon vesuvianum, on granite blocks of dry stone wall

Forms compact tufts of erect or decumbent grey-white pseudopodetia, branched or unbranched. Small phyllocladia usually with dark grey centres and pale margins. Very variable in form. Common in upland areas on siliceous rocks. Stereocaulon vesuvianum var. vesuvianum Lichen Species (

Named after its identification as a pioneer role on lava on Vesuvius. .The dominant lichen of the Somma-Vesuvius lava is certainly the Stereocaulon vesuvianum, with a typical grey and stringy appearance, which can be found on the most ancient lava flows along with the pioneering shrub species The pioneer species | Vesuvius National Park (

Tormentil, Potentilla erecta and Common Heater (Ling), Calluna vulgaris

A Rowan, Sorbus aucuparia

Probably Reindeer Moss (lichen), Cladonia rangiferina, with heathers on the granite outcrop north of the dam

Llyn Trawsfynydd (reservoir)

Afon Prysor Gorge from dam; showing the peat bog to the south of the gorge

The dam

Returning to Maentwrog HEP station (the start of my walk) from the Dam

Stonechat, Saxicola rubicola

Flavoparmelia sp. lichen, probably F. caperata on Sessile Oak

Racomitrium lanuginosum, Woolly Fringe-moss

Afon Prysor gorge

Ochrolechia androgyna, Powdery Saucer Lichen, on Sessile Oak

This pale grey crust often forms extensive sheets on trees and rocks. The thalllus varies from thin and fairly smooth to thick, lumpy and cracked. Pale yellow to yellowish green, convex soralia with granular soredia are prominent and may extend to cover most of the surface except near the edge. Apothecia are usually absent but when present have a pink-orange disc with a pale margin. ... Habitat: On acid-barked deciduous trees and conifers. Also on siliceous rock including drystone walls and scree. It may also form a thin cover over moss. Distribution: Widespread and often common, mainly in the uplands of Britain and Ireland. Ochrolechia androgyna (

This example was clearly fertile; mostly this lichen is seen infertile. But I noted on my trip to North-Western Scotland that lichens which are typically infertile elsehwere can be fertile in temperate rain forest climates e.g. the Bunodophoron melanocarpum in Sussex (rare) is infertile, but in Glen Nant (Argyle ) it is fertile

One of the tributary streams to the Afon Prysor

Probably an Amanita sp. fungus

Polypodium sp, probably P. vulgare, with mosses growing between granite blocks

Common Mouse-Ear, Cerastium fontanum; in a meadow, attached to a former farmstead

Waterfall on a tributary of the Afon Prysor



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